Processes for upgrading a hydrocarbon feed

A process for upgrading a hydrocarbon feed, the process comprising:

• separating the hydrocarbon feed to produce at least one distillation fraction and a heavy oil stream;
• treating a sulfur-containing hydrocarbon stream in a sweetening process to produce a reduced-sulfur hydrocarbon stream and a disulfide oil stream, wherein the disulfide oil stream comprises disulfide compounds having the general formula (I):
• R
• 1
• ⁢
• —
• ⁢
• S
• ⁢
• —
• ⁢
• S
• ⁢
• —
• ⁢
• R
• 2
• (
• I
• )
• where R1 and R2 are both hydrocarbyl groups;
• combining at least a portion of the heavy oil stream and the disulfide oil stream in a mixing unit to produce a cracker feed, wherein the cracker feed comprises from 3 wt. % to 30 wt. % of the disulfide oil stream based on the total weight of the cracker feed;
• passing the cracker feed to a thermal cracking system comprising a thermal cracking unit and a thermal separation system downstream of the thermal cracking unit;
• thermally cracking the cracker feed in the thermal cracking unit to produce solid coke and a cracking effluent comprising one or more liquid reaction product, one or more gaseous reaction products, or both, where the presence of the disulfide oil stream promotes conversion of hydrocarbons from the heavy oil stream to the one or more liquid reaction products, the one or more gaseous reaction products, or both over conversion of hydrocarbons from the heavy oil stream to the solid coke;
• passing the cracker effluent to a cracker effluent separation system that separates the cracker effluent into one or more product effluents and a cracker bottom stream;
• passing the cracker bottom stream from the cracker effluent separation system to the thermal cracking unit using a transfer pump to increase a pressure of the cracker bottom stream to a pressure of from 150 psig to 400 psig.